A variety of electronic and optoelectronic devices can be enabled by developing thin film relaxed lattice constant III-V semiconductors on elemental silicon (Si) substrates. Surface layers capable of achieving the performance advantages of III-V materials may host a variety of high performance electronic devices such as complementary metal oxide semiconductor (CMOS) and modulation doped quantum well (QW) transistors fabricated from extreme high mobility materials such as, but not limited to, indium antimonide (InSb), indium gallium arsenide (InGaAs) and indium arsenide (InAs). Modulation doping is provided by doping a wide band gap semiconductor layer grown adjacent to a narrow gap semiconductor, forming a heterostructure. High mobility, modulation doped quantum well devices require the formation of several perpendicular epitaxially grown layers, making them incompatible with previous non-planar transistor fabrication techniques.